Problem: Simplify the following expression: ${3p+9(p-7)}$
Solution: Distribute the ${9}$ into the parentheses: $ 3p + {9(}\gray{p-7}{)} $ $ 3p + {9p-63} $ Combine the $p$ terms: $ {3p + 9p} - 63$ $ {12p} - 63$ The simplified expression is $12p-63$